The cost of 4 pens is Rs 30.kelina buys 5 pens How much will she pay ?

Hello,

the cost of 4 pens is Rs 30.

So, the cost of 1 is 30 divided by 4 = 7,5 Rs

And then, the cost of 5 is : 5 x 7,5 = 37,5 Rs

...though I don(t know what are Rs :)

HELLO,
4 pens= Rs 30
1 pens= Rs 7,5

30×1÷4= Rs 7,5
5 pens = 7,5×5= Rs 37,5